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Weyl-Kondo semimetal behavior in the chiral structure phase of Ce$$_{3}$$Rh$$_{4}$$Sn$$_{13}$$

岩佐 和晃*; Suyama, Kazuya*; 河村 聖子; 中島 健次; Raymond, S.*; Steffens, P.*; Yamada, Akira*; 松田 達磨*; Aoki, Yuji*; 川崎 郁斗; et al.

Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01

The spin dynamics, crystalline-electric-field (CEF) level scheme, specific heat, and X-ray photoemission spectra (XPS) of Ce$$_{3}$$Rh$$_{4}$$Sn$$_{13}$$ were investigated, which exhibits anomalous semimetal transport in the chiral crystallographic phase. CEF excitations observed at approximately 7 and 39 meV are consistent with the two inequivalent Ce-ion cites in the chiral structure. Because of broader CEF excitations and a strong 4$$f^{1}$$ peak at the Fermi level in the Ce 4$$f$$ on-resonance spectrum, the hybridized Ce 4$$f$$ electrons contribute to the semimetal carriers. In addition, the spin fluctuation associated with the Kramers doublet ground state is characterized by the peak located at 0.15 meV. The electronic state involving the spin fluctuation causes the $$T^{3}$$ behavior of specific heat below 0.6 K, which is attributed to linear dispersion relations of electrons of the Weyl Kondo semimetal in the chiral-lattice symmetry.


Core and safety design for France-Japan common concept on sodium-cooled fast reactor

高野 和也; 大木 繁夫; 小澤 隆之; 山野 秀将; 久保 重信; 小倉 理志*; 山田 由美*; 小山 和也*; 栗田 晃一*; Costes, L.*; et al.

EPJ Nuclear Sciences & Technologies (Internet), 8, p.35_1 - 35_9, 2022/12



Extended X-ray absorption fine structure spectroscopy measurements and ${it ab initio}$ molecular dynamics simulations reveal the hydration structure of the radium(II) ion

山口 瑛子; 永田 光知郎*; 小林 恵太; 田中 万也; 小林 徹; 谷田 肇; 下条 晃司郎; 関口 哲弘; 金田 結依; 松田 晶平; et al.

iScience (Internet), 25(8), p.104763_1 - 104763_12, 2022/08

 被引用回数:1 パーセンタイル:40.23(Multidisciplinary Sciences)




山口 瑛子; 永田 光知郎*; 田中 万也; 小林 恵太; 小林 徹; 下条 晃司郎; 谷田 肇; 関口 哲弘; 金田 結依; 松田 晶平; et al.

放射化学, (45), p.28 - 30, 2022/03



High spatial resolution neutron transmission imaging using a superconducting two-dimensional detector

宍戸 寛明*; 西村 和真*; Vu, TheDang*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; et al.

IEEE Transactions on Applied Superconductivity, 31(9), p.2400505_1 - 2400505_5, 2021/12

 被引用回数:0 パーセンタイル:0(Engineering, Electrical & Electronic)

中性子イメージングは、重金属に対する高透過性、軽元素に対する高感度、同位体と中性子との特異な核反応による同位体選択性などの中性子ビームの特徴を活かした非破壊検査の有力な手段の一つである。本研究では、超伝導検出器である電流バイアス運動インダクタンス検出器(CB-KID)を用いて、パルス中性子源を用いた飛行時間法による波長分解中性子イメージングを行った。遅延時間型CB-KIDを用いて、GdAl$$_{3}$$単結晶を成長させたGd-Al合金試料の中性子透過像を取得した。その結果、単結晶はAl-Gd合金全体に渡って、形状,分布ともに良好に観察することができた。また、中性子の波長0.03nm以上でGdによる特徴的な中性子の吸収を確認した。さらに、15$$mu$$m$$ times$$ 12$$mu$$mという限られた検出面で、同位体と中性子の核反応によって生じる$$^{155}$$Gd共鳴ディップを観測することができた。また、$$^{155}$$Gdの共鳴ディップを用いてGd選択的イメージングを行ったところ、中性子の波長幅が1pmという限られた範囲で、明確なGd核の元素選択イメージング像を取得することに成功した。


Practical tests of neutron transmission imaging with a superconducting kinetic-inductance sensor

Vu, TheDang; 宍戸 寛明*; 相澤 一也; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 奥 隆之; 曽山 和彦; 宮嶋 茂之*; et al.

Nuclear Instruments and Methods in Physics Research A, 1006, p.165411_1 - 165411_8, 2021/08

 被引用回数:0 パーセンタイル:0.02(Instruments & Instrumentation)

We found that the sizes of the Gd islands determined from the transmission image correlated strongly with those determined from the SEM image. We demonstrated the CB-KID could be used to identify (1) tiny voids in a thermally sprayed continuous Gd$$_2$$O$$_3$$ film in and (2) various mosaic morphologies and different eutectic microstructures in Wood's metal samples. The fact that the CB-KID system could be used to identify features of samples with a wide distribution of sizes and thicknesses is promising for real application of the device for imaging samples of interest to material scientists. Operating the CB-KID at higher temperatures appreciably improved the efficiency for simultaneously identifying the X and Y positions of hotspots. We also compared the detection efficiency with the PHITS simulations. We now plan to improve the detection efficiency by increasing the thickness of the $$^{10}$$B neutron conversion layer


Homogeneity of neutron transmission imaging over a large sensitive area with a four-channel superconducting detector

Vu, TheDang; 宍戸 寛明*; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 宮嶋 茂之*; 奥 隆之; 曽山 和彦; 相澤 一也; et al.

Superconductor Science and Technology, 34(1), p.015010_1 - 015010_10, 2021/01

 被引用回数:3 パーセンタイル:44.08(Physics, Applied)

We demonstrated that a four-readout superconducting neutron imaging system shows good spatial heterogeneity and linearity using the delay-line method. We examined the precise pattern of a $$^{10}$$B-dot-array absorber and found the X-direction pitch (Px) = 250.7 um with a scatter of (Hx)= 5.4 um and the Y-direction pitch (Py)= 249.1 um with a scatter of (Hy)= 3.4 um while the $$^{10}$$B dot array was fully extended toward the X direction across the detector sensitive area. We consider that this demonstrates detection with good spatial homogeneity and conclude. The transmission-imaging system is suitable for use at pulsed neutron facilities. We also reported a clear transmission image of tiny screws and nuts, and ladybug (insect). We recognize that further efforts to improve the detection efficiency are necessary to make using the detector more practical.


Kinetic inductance neutron detector operated at near critical temperature

Vu, TheDang; 西村 和真*; 宍戸 寛明*; 原田 正英; 及川 健一; 宮嶋 茂之*; 日高 睦夫*; 奥 隆之; 曽山 和彦; 相澤 一也; et al.

Journal of Physics; Conference Series, 1590, p.012036_1 - 012036_9, 2020/07

 被引用回数:0 パーセンタイル:0.01

Our CB-KID neutron imager detects high spatial resolution neutrons transmission images by using a delay-line technique. We found that the number of events was remarkably increased with increasing the detector temperature until close to the critical temperature Tc. We investigated the properties of CB-KID at near Tc. We observed systematic changes of neutron signals as a function of the detector temperature from 4 K to Tc. The simulations modeled the sequential physical processes for $$^{10}$$B(n,$$alpha$$)$$^{7}$$Li reactions and energy deposition by particles within CB-KID, including neutrons, $$^{4}$$He particles, $$^{7}$$Li particles, photon and electron transport.


Energy-resolved neutron imaging with high spatial resolution using a superconducting delay-line kinetic inductance detector

飯澤 侑貴*; 宍戸 寛明*; 西村 和真*; Vu, TheDang*; 小嶋 健児*; 小山 富男*; 及川 健一; 原田 正英; 宮嶋 茂之*; 日高 睦夫*; et al.

Superconductor Science and Technology, 32(12), p.125009_1 - 125009_8, 2019/12

 被引用回数:11 パーセンタイル:60.35(Physics, Applied)

Neutron imaging is one of the key technologies for non-destructive transmission testing. Recent progress in the development of intensive neutron sources allows us to perform energy-resolved neutron imaging with high spatial resolution. We have been developing a neutron imager aiming at conducting high spatial and temporal resolution imaging based on a delay-line neutron detector, called the current-biased kinetic-inductance detector, with a conversion layer $$^{10}$$B. The detector allowed us to obtain a neutron transmission image with four signal readout lines. Herein, we expanded the sensor active area, and improved the spatial resolution of the detector. We examined the capability of high spatial resolution neutron imaging over the sensor active area of 15 $$times$$ 15 mm$$^{2}$$ for various samples, including biological and metal ones. We also demonstrated an energy-resolved neutron image in which stainless-steel specimens were discriminating of other specimens with the aid of the Bragg edge transmission.


Temperature dependent characteristics of neutron signals from a current-biased Nb nanowire detector with $$^{10}$$B converter

Vu, TheDang; 飯澤 侑貴*; 西村 和真*; 宍戸 寛明*; 小嶋 健児*; 及川 健一; 原田 正英; 宮嶋 茂之*; 日高 睦夫*; 奥 隆之; et al.

Journal of Physics; Conference Series, 1293, p.012051_1 - 012051_9, 2019/10

 被引用回数:5 パーセンタイル:95.3

We succeeded in designed and fabricated a neutron detector by using a superconducting current-biased kinetic inductance detector (CB-KID), which is constructed by two perpendicular Nb-based superconducting meander-lines and an enriched $$^{10}$$B neutron conversion layer. We rebuilt completely a neutron image of a $$^{10}$$B dot array contain in the stainless-steel mesh. To improve the resolution of neutron images, the characteristics of a superconducting neutron detector have been studied carefully. In this study, we present the dependence of neutron signals in the temperature of detector. We found that when the temperature of a neutron detector is as close as the critical temperature of superconductivity, the intensity of signal increase as a function of temperature. We consider that the ratio of noise and signal is decrease which is very useful to improve the resolution of neutron images.


Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; 大津 秀暁*; 千賀 信幸*; 川瀬 頌一郎*; 武内 聡*; 炭竃 聡之*; 小山 俊平*; 櫻井 博儀*; 渡辺 幸信*; 中山 梓介; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 被引用回数:7 パーセンタイル:57.83(Physics, Multidisciplinary)



Coolability evaluation of debris bed on core catcher in a sodium-cooled fast reactor

松尾 英治*; 佐々 京平*; 小山 和也*; 山野 秀将; 久保 重信; Hourcade, E.*; Bertrand, F.*; Marie, N.*; Bachrata, A.*; Dirat, J. F.*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 5 Pages, 2019/05



SAS4A analysis study on the initiating phase of ATWS events for generation-IV loop-type SFR

久保田 龍三朗; 小山 和也*; 森脇 裕之*; 山田 由美*; 島川 佳郎*; 鈴木 徹; 川田 賢一; 久保 重信; 山野 秀将

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04



Model verification and validation procedure for a neutronics design methodology of next generation fast reactors

大釜 和也; 池田 一三*; 石川 眞; 菅 太郎*; 丸山 修平; 横山 賢治; 杉野 和輝; 長家 康展; 大木 繁夫

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04

Detailed model verification & validation (V&V) and uncertainty quantification (UQ) procedure for our deterministic neutronics design methodology including the nuclear library JENDL-4.0 for next generation fast reactors was put into shape based on a guideline for reliability assessment of simulations published in 2016 by the Atomic Energy Society of Japan. The verification process of the methodology was concretized to compare the results predicted by the methodology with those by a continuous-energy Monte Carlo code, MVP with their precise geometry models. Also, the validation process was materialized to compare the results by the methodology with a fast reactor experimental database developed by Japan Atomic Energy Agency. For the UQ of the results by the methodology, the total value of the uncertainty was classified into three factors: (1) Uncertainty due to analysis models, (2) Uncertainty due to nuclear data, and (3) Other uncertainty due to the differences between analysis models and real reactor conditions related to the reactor conditions such as fuel compositions, geometry and temperature. The procedure to evaluate the uncertainty due to analysis models and uncertainty due to nuclear data was established.


Numerical study on influence of Ohnesorge number and Reynolds number on the jet breakup behavior using the lattice Boltzmann method

岩澤 譲*; 阿部 豊*; 金子 暁子*; 金川 哲也*; 齋藤 慎平*; 松尾 英治*; 海老原 健一; 坂場 弘*; 小山 和也*; 成合 英樹*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05




松尾 英治*; 阿部 豊*; 岩澤 譲*; 海老原 健一; 小山 和也*

日本機械学会論文集(インターネット), 81(822), p.14-00409_1 - 14-00409_20, 2015/02



A Scenario of core disruptive accident for Japan sodium-cooled fast reactor to achieve in-vessel retention

鈴木 徹; 神山 健司; 山野 秀将; 久保 重信; 飛田 吉春; 中井 良大; 小山 和也*

Journal of Nuclear Science and Technology, 51(4), p.493 - 513, 2014/04

 被引用回数:64 パーセンタイル:98.65(Nuclear Science & Technology)



格子ボルツマン法HCZモデルによるジェットブレイクアップ挙動評価,1; ブレイクアップ長さの評価

松尾 英治*; 阿部 豊*; 岩澤 譲*; 海老原 健一; 金子 暁子*; 坂場 弘*; 小山 和也*

第18回動力・エネルギー技術シンポジウム講演論文集, p.75 - 76, 2013/06



格子ボルツマン法HCZモデルによるジェットブレイクアップ挙動評価,2; ブレイクアップに及ぼす周囲流動場の影響

岩澤 譲*; 阿部 豊*; 松尾 英治*; 海老原 健一; 金子 暁子*; 坂場 弘*; 小山 和也*

第18回動力・エネルギー技術シンポジウム講演論文集, p.77 - 78, 2013/06



Influence of fragmentation on jet breakup behaviour

岩澤 譲*; 阿部 豊*; 金子 暁子*; 黒田 泰平*; 松尾 英治*; 海老原 健一; 坂場 弘*; 小山 和也*; 伊藤 和宏*; 成合 英樹*

Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 12 Pages, 2013/05


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